Abstract:

The Marine Mammal Programme (MMP) conducts research on pinnipeds and killer whales Orcinus
orca at Marion Island, Prince Edward Islands, under the auspices of the Mammal Research Institute,
Department of Zoology and Entomology, University of Pretoria. The history of the MMP, which has
benefited from collaboration with leading national and international researchers, is described from its
start through to current research. The setting up of long-term studies such as the mark-resighting of
southern elephant seals Mirounga leonina commenced in 1983. The elephant seal population declined
by 87% between an initial census in 1951 and 2004. This was followed by a stabilisation period and a
current increase. The recovery, and subsequent increase of sympatric populations of Subantarctic fur
seals Arctocephalus tropicalis and Antarctic fur seals A. gazella (following cessation of commercial
sealing), are documented. Insights into many aspects of elephant seal and fur seal biology, including
life history, demography, diet, growth, foraging and ranging behaviour are described. Ancillary work
on morphology, genetics, anthropogenic influences and rare events are mentioned, as well as the
extent of current research that addresses population dynamics in an ecosystem context. Opportunistic
photographic identification of killer whales and recent dedicated observations at Marion Island are
used to determine population size, seasonal abundance and sociality of this population, and to further
understanding of its potential impact on resident pinniped populations.